3-hydroxyisothiazoles

ABSTRACT

DISCLOSED HEREIN ARE CERTAIN NOVEL COMPOUNDS WHICH ARE MOST PROPERLY DESIGNATED AS SUBSTITUTED 3-HYDROXYISOTHIAZOLES AND SALTS OF 3-HYDROXYISOTHIAZOLES. THESE COMPOUNDS AND COMPOSITIONS CONTAINING THEM EXHIBIT A BROAD SPECTRUM OF BIOCIDAL PROPERTIES AND ARE PARTICULARLY EFFECTIVE FOR THE CONTROL OF MICROOGANISMS.

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3,801,575 ited Apr. 2, 1974 24, 1972, Ser. No. 219,937

Int. Cl. C07d 91/12 US. Cl. 260--247.1 15 Claims ABSTRACT OF THEDISCLOSURE Disclosed herein are certain novel compounds which are mostproperly designated as substituted 3-hydroxyisothiazoles and salts of3-hydroxyisothiazoles. These compounds and compositions containing themexhibit a broad spectrum of biocidal properties and are particularlyeffective for the control of microorganisms.

CROSS-REFERENCES TO RELATED APPLICATIONS by the formula.

l t z' 1 wherein Z is hydrogen, lower alkyl, carboxy, lower carbalkoxy,

carbamoyl, nitro, halogen, or cyano;

Z, when Z is cyano, carboxy, lower carbalkoxy, or carbamoyl, ishydrogen, lower alkyl, aralkyl of up to 8 carbon atoms, halogen, loweralkylsulfinyl, aralkylsulfinyl of up to 8 carbon atoms, loweralkylsulfonyl, aralkylsulfonyl of up to 8 carbon atoms, lower alkylthio,alkylamino of up to 8 carbon atoms, or aralkylamino of up to 8 carbonatoms;

Z, when Z is nitro, is hydrogen, lower alkyl, aralkyl of up to 8 carbonatoms, or halogen;

Z, when Z is lower alkyl, is hydrogen, lower alkyl, aralkyl of up to 8carbon atoms, halogen, or lower haloalkyl;

Z, when Z is halogen, is hydrogen, aralkyl of up to 8 carbon atoms,halogen, or lower haloalkyl; and

Z, when Z is hydrogen, is an alkyl group of 4 to 12 carbon atoms,aralkyl of up to 8 carbon atoms, halogen or lower haloalkyl.

Where the expression lower is employed in conjunc= tion with terms, suchas for example, alkyl, alkylsulfinyl,

alkylsulfonyl, or haloalkyl, it is intended to indicate that the alkylportion thereof has a carbon content of 1 to 4 carbon atoms. Typically,the alkyl or alkyl portion may be methyl, ethyl, propyl, isopropyl,butyl, t-butyl and the like.

It should be noted at this point that the bulk of available physicaldata suggests that Formula I properly designates the isothiazoles ofthis invention. However, these compounds are tautomeric with theirketo-forms which may be represented by the following formula T 1 NH 2\s/ (H) For this reason, the isothiazoles can exist in either con=figuration or as a mixture in any proportion of both forms, andtherefore, any reference to either formula herein is intended to includethe other.

The 3-hydroxyisothiazoles of the invention can form novel acid and basesalts which also exhibit biocidal activity. The novel acid salts of theinvention can be repre sented by the formula wherein Z and Z are asdescribed above, and Q is an alkali, alkaline earth, or transition metalcation; a quaternary ammonium or phosphonium cation; or, a primary,secondary, or tertiary organic base cation.

Among the cations and compounds which Q can represent are inorganiccations such as Na Zn++, Cd++, Fe++, Cu++, Co++, Ni++, Fe+++, and thelike, organic cations such as benzyldimethylalkylammonium,tetramethylammonium, (B hydroxyethylethyl) trimethylammonium,tetramethylphosphonium, and the like, and organic basecatrimethylammonium, tetramethylphosphonium, and the like, and organicbase cations such as benzylamrnonium, morpholinium,N,N'-di-n-decylformamidinium, N,N-di-t-octylformamidinium, and the like.

The novel base salts of the invention can be represented by the formulaI: Z n- 0 H]+ A- z I H wherein Z and Z are as described above, and A isthe anion of a strong inorganic acid or a strong organic acid, ssuch asa carboxylic acid, sulfonic acid, or a phosphonic tacid.

Among the anions which A can represent are Cl", N02", C104, 804 HSOr,

4-bromo-3-hydroxyisothiazole,

4-chloro-3 -hydroxyisothiazole,

5-benzyl-3 -hydroxyisothiazole,

5-bromo-3 -hydroxyisothiazole,

5-chloro-3 -hydroxyisothiazole,

4,5 -dichloro-3 -hydroxyisothiazo1e, 4,5-dibromo-3-hydroxyisothiazole,4-chloro-S-bromo-3-hydroxyisothiazo1e,4-bromo-5-chloro-3-hydroxyisothiazole,v4-chloro-5-benzyl-3-hydroxyisothiazole,4-bromo-5-benzyl-3-hydroxyisothiazole, 4-methyl-3 -hydroxyisothiazole,

4-ethyl-3 -hydroxyisothiazle, 4-butyl-3-hydroxyisothiazole,4-methyl-S-ethyl-3 -hydroxyisothiazole,

4,5 -dimethyl-3-hydroxyisothiazole,4-methyl-5-ehloro-3-hydroxyisothiazole, 4-propyl-5-chloro-3-hydroxyisothiazole, 4-butyl-5-chloro-3-hydroxyisothiazole,4-methyl-5-bromo-3-hydroxyisothiazole, 4-ethyl-5-bromo-3-hydroxyisothiazole, 4-ethyl-5-benzyl-3-hydroxyisothiazole,4-propyl-5-benzyl-3 -hydroxyisothiazole,4-cyano-5-methylsulfinyl-3-hydroxyisothiazole,4-cyano-5-ethylsulfinyl-3-hydroxyisothiazole,4-cyano-5-benzylsulfinyb3-hydroxyisothiazole, 4-cyano-5-methylsulfonyl-3-hydroxyisothiazole, 4-cyano-5-butylsulfonyl-3 hydroxyisothiazole,4-cyano-5-benzylsulfonyl3-hydroxyisothiaz0le, 4-carboxy-3-hydroxyisothiazole, 4-carbamoyl-3-hydroxyisothiazole,4-nitro-3-hydroxyisothiazole,4-carboxy-5-methylthio-3-hydroxyisothiazole,4-carbamoyl-5-methylthio-3-hydroxyisothiazole,4-cyano-5-n-butylamino-3-hydroxyisothiazole,4-cyano-5-ethylarnino-3-hydroxyisothiazole 4-iodo-3 -hydroxyisothiazole,4-cyano-3-hydroxyisothiazole, 4-carbethoxy-3-hydroxyisothiazole,4-nitro-S-chloro-3-hydroxyisothiazole, and4-cyano-5-methyl-3-hydroxyisothiazole.

Generally, the isothiazoles disclosed herein may be classified intoseveral types dependent upon their substitutions at the 4 and 5positions. The preparation of these compounds is more readily followedby means of this classification. These types of compounds are asfollows:

4-halo-3-hydroxyisothiazole 4-halo-5-aralky1-3-hydroxyisothiazole4,5-dihalo-3-hydroxyisothiazole 5-halo-3-hydroxyisothiazole4,S-dihalo-S-hydroxyisothiazole 4-alkyl-3-hydroxyisothiazo1e4,5-dialkyl-3-hydroxyisothiazole 4-alkyl-5-halo-3-hydroxyisothiazole4-alkyl-5-aralkyl-3-hydroxyisothiazole 5-aralkyl-3-hydroxyisothiazole-4-halo-5-aralkyl-3 -hydroxyisothiazole 4,5-dialkyl-3-hydroxyisothiazole4-cyano-5-alkylsulfonyl-3-hydroxyisothiarole 4-cyano-5-aralkylsulfonyl-3-hydr0xyisoth1azole 4-cyano-3-hydroxyisothiazole 4-carboxy-3-hydroxyisothiazole 4-carbamoyl-3-hydroxyisothiazole4-nitro-3-hydroxyisothiazole 4cyano5-alkyl-3-hydroxyisothiazole4-carboxy-5-alkyl-3 -hydroxyisothiazole 4-carbamoyl-5-alkyl-3-hydroxyisothiazole 4-nitro-5-alkyl-3-hydroxyisothiaz0le4-cyano-5-halo-3-hydroxyisothiazole4-carboxy-5-halo-3-hydroxyisothiazole4-carbamoyl-5-halo-3-hydroxyisothiazo1e4-nitro-5-halo-3-hydroxyis0thiazole4-cyano-5-alkylamino-3-hydroxyisothiazole4-carbalkoxy-5-alky1-3-hydroxyisothiazole'4-carbalkoxy-S-halo-3-hydroxyisothiazole 4-carbalkoxy-5-alkylsulfiny1-3 -hydroxyisothiazole4-carbalkoxy-5-alkylsu1fonyl-3-hydroxyisothiazole Type A compounds canbe prepared by halogenation of 3-hydroxyisothiazole or of substituted3-hydroxyisothiazoles with a suitable halogenating agent.3-hydroxyisothiazole is a known compound in the literature and may besynthesized from propiolamide by the method of W. D. Crow and N. J.Leonard, J. Org. Chem., 30, 2660-2665 (1965). Preparation of thesubstituted 3-hydroxyisothiazoles is set forth under the Type Ccompounds. Any halogenating agent may be employed in this reaction.Typical halogenating agents include chlorine, bromine, sulfurylchloride, sulfuryl bromide, N-chlorosuccinimide, N-brornosuccinimide,iodine monochloride, and the like. Bromine and chlorine are preferredhalo genating agents. The halogenation reaction is preferably carriedout in an inert organic solvent. Aromatic hydrocarbons, halogenatedaromatic hydrocarbons, halogenated aliphatic hydrocarbons, ketones,esters and amides are representative of such solvents. The reaction isexothermic and proceeds readily when conducted at about C. to -20 C. orbelow. Generally, equimolar ratios of the reactants are utilized.

Compounds falling within the type B category can be prepared by thecyclization of a disulfide-amide having the formula 1: o (-sonbuiimn) iwherein X and Z are hydrogen or lowerallcyl. The cycli= zation isaccomplished by reacting the disulfide-amide with a halogenating agent.Cyclization of the disulfide amide will take place when 3 moleequivalents of halo-= genating agent are employed in the reaction. Byproviding an excess of halogenating agent, the isothiazole may behalogenated at the 4- and/or 5-positions of Formula I. Where 5 moleequivalents of halogenating agent are avail= able, mono-halogenation canbe effected. For di-halogenation, 7 mole equivalents of halogenatingagent are stoichiometric. Preparation of isothiazoles having the 4- and5-positions substituted with different halogens is achieved by thehalogenation of an isothiazole already halogenated at one of the twopositions. For example, if a 4-brom0- 5-chloro-3-hydroxyisothiazole isdesired, it can be obtained by bromination of a5-chloro-3-hydroxyis0thiazole or the chlorination of a4-bromo-3-hydroxyisothiazoleo The starting 3-hydroxyisothiazole isprepared by the cy= cl aation of a disu fi e-am de as escribed above.The ey clization process will proceed over a broad temperature range andtemperature is not critical to the reaction. Generally, the cyclizationwill be carried out in the range of to 100 C. The reaction is carriedout in an inert nonaqueous solvent, such as, for example, benzene,toluene, xylene, ethyl acetate, or ethylene dichloride. In addition, the4,S-dihalo-S-hydroxy-isothiazoles, may be prepared by in situhalogenation of a S-halo-3-hydroxyisothiazole, as described for type Acompounds.

Type C compounds are prepared by the method of Goerdeler and Mittler asdescribed in Chem. Ber., 96, 944-954 (1963). This involves thehalogenation of a substituted fi-thioketoamide in an inert organic estersolvent such as ethyl acetate. Such a reaction may be represented by thefollowing equation:

where R is hydrogen or lower alkyl; and R is aralkyl of up to 8 carbonatoms or lower alkyl.

When two moles of halogenating agent per mole of thioketoamide areemployed in the reaction, 4-halo-5- aralkyl-3-hydroxyisothiazoles can beprepared. The reaction proceeds smoothly at a temperature in the rangeof about 40 to 0 C. or below.

Another process for preparing the type C S-aralkyl-3-hydroxyisothiazoles is that of Crow and Leonard as set forth in theJournal of Organic Chemistry reference cited above. This method involvesthe converting of a B-substituted thiocyanoacrylamide orthiosulfatoacrylamide to the hydroxyisothiazole. This reaction may berepresented by the following equation:

R H 0H \C'=C/ B l LE Y CONHr s wherein R" is aralkyl of up to 8 carbonatoms and Y is -SCN or S O Preferably, conversion of the substitutedthiocyanoacrylamide or thiosulfatoacrylamide to the hydroxyisothiazoleis achieved by treating the amide with an acid, such as, for example,sulfuric acid. However, when Y is SCN, then transition metal salts, suchas nickel sulfate, ferrous sulfate, ferric sulfate, copper sulfate andthe like, can also be readily utilized, and when Y is S 0 iodine canalso be used. Preparation of the thiocyanoacrylamide andthiosulfatoacrylamide as taught by Crow and Leonard is achieved byreacting a substituted propiolamide with thiocyanic acid or thiosulfate.

Type D compounds are prepared by oxidizing a S-thioalkyl or-thioaralkyl-4-cyano-3-hydroxyisothiazole. The latter compound isprepared by the reaction of an alkylhalide or aralkylhalide, such asmethyl iodide, ethyl iodide, benzyl chloride, and the like, withB-hydroxy-S-mercapto- 4-cyano-isothiazole dipotassium salt followed byacidification. This process is described in the literature by W. R.Hatchard, J. Org. Chem., 28, 2163-2164 (1963). Oxidizing agents wouldinclude, for example, organic peracids such as peracetic,m-chloroperbenzoic, and perphthalic acids or inorganic oxidizing agentssuch as hydrogen peroxide or nitric acid. The oxidizer is employed insubstantially equimolar quantities with the isothiazole. A temperatureof 40 C. to 0 C. or below is satisfactory for the reaction which isgenerally carried out in an inert organic solvent. Representativesolvents which may be uti-.

lized include aromatic hydrocarbons, aliphatic hydrocarbons, chlorinatedaromatic and aliphatic hydrocarbons, ketones, esters, amides and thelike.

Type E hydroxyisothiazoles are prepared by the same general methodsemployed for the preparation of type D compounds except that two molesof oxidizing agent per mole of the S-thioalkyl or 5 thioaralkyl4-cyano-3= hydroxyisothiazole are required.

Type F compounds can be prepared by reacting the appropriate 4-cyano,4-carboxy, 4-nitro, or 4-carbamoy1- -3-methoxyisothiazole with hydrogenbromide. The 4- cyano-3-methoxyisothiazoles are prepared from 3-methoxyisothiazoles, which are in turn prepared by the cy= clization of adisulfide-imidate of the formula wherein R is hydrogen or an alkylgroup, by a process similar to the cyclization of disulfide-amides whichis described above as a process for preparing the type B compounds. The3-methoxyisothiazole is then converted to the4-bromo-3-methoxyisothiazole by treatment with a halogenating agent by aprocess as in the preparation of the Type A compounds described above.

The 4-br0mo-3-methoxyisothiazole is then reacted with an equimolar orexcess amount of cuprous cyanide, in a polar, non-hydroxylic solventsuch as dimethylformamide, to give the 4-cyano-3-methoxyisothiazole. The4- carba-moyl-3-methoxyisothiazoles are prepared by the hydrolysis of4-cyano-3-methoxyisothiazoles with sulfuric acid. When the carbamoylderivative is hydrolyzed with nitrous acid, a4-carboxy-S-methoxyisothiazole is obtained. In the demethylationreactions, an equimolar amount or an excess of sulfuric acid or nitrousacid is used, and the reactions can be carried out in a wide variety ofsolvents. The S-halo and 5-alkyl-4-carboxyl and4-carbamoyl-3-methoxyisothiazoles are prepared from the corresponding4-cyano-3-methoxyisothiazole, which is in turn prepared from3-methoxyisothiazole.

The 4-nitro-3-methoxyisothiazoles are prepared by a classical nitrationof 3-methoxyisothiazole in a nitric acid-sulfuric acid mixture,generally using an equimolar amount of nitric acid and excess sulfuricacid.

The Type G compounds can 'be prepared by extension of the method of J.Goerdeler and U. Keuser, Chem. Ber., 97, 3106 (1964). This methodinvolves the cyclization of a substituted a-cyanothiomalonamide with ahalogenating agent in a non-hydroxylic solvent, such as benzene,toluene, ethyl acetate, ethylene dichloride, and the like. Thea-cyanothiomalonamides are prepared by the reaction of cyanoacetamidewith an alkylisothiocyanate in the presence of a strong base in anon-hydroxylic solvent. The reaction scheme may be represented by thefollowing equations:

wherein R is an alkyl group of one to eight carbon atoms. Generally, anequimolar or an excess amount of the base and halogenating agent areused, and the reaction proceeds satisfactorily when carried out at about0 to about 60 C.

Type H compounds are prepared by esterification of the respective4-carboxy-3-hydroxyisothiazoles using ex cess alcohol as solvent and anacid catalyst, such as hydrogen chloride or p-toluene sulfonic acid.

A wide variety of methods can be employed to produce the3-hydroxyisothiazole salts of the invention. The metal salts of FormulaII can be prepared by adding a metal oxide to an aqueous solution of theisothiazole, or by adding a metal salt to an aqueous solution of theisothiazole which has been neutralized with a strong base, such aspotassium hydroxide or sodium hydroxide. The metal 3-hydroxyisothiazolesalt will generally precipitate out at once or after standing for aperiod, and this precipitate can be filtered off and washed with water.

-In preparing some metal salts of the 3-hydroxyiso-= The salts ofS-hydroxyisothiazoles with strong inorganic acids of Formula IV can beprepared by bubbling an anhydrous acid, such as hydrogen bromide orhydrogen chloride through a solution of the isothiazole in an inertorganic solvent, such as chloroform or ethyl ether. These salts can alsobe prepared by adding the 3- hydroxyisothiazole to a concentratedaqueous solution of the acid. In both of these processes, the salt willprecipitate and can be conveniently filtered off. The salts of3-hydroxyisothiazoles with strong organic acids can be prepared byadding the acid to a solution of the isothiazole in an inert organicsolvent. If no precipitate forms immediately, the solution can then becooled and crystallization of the salt induced. The salts of Formula IIIwith organic bases can be prepared by adding an equivalent amount of thebase to a solution of the isothiazole in an inert organic solvent. Aprecipitate may form immediately, or cooling of the solution orevaporating off the solvent may be necessary to cause the salt tocrystallize.

By way of demonstration, the following examples are offered toillustrate this invention and are not to be construed as limitationsthereof. In the examples, parts are by weight unless otherwiseindicated. Examples 1 through 18 are tabulated in Table 1, Examples 19through 37 in Table Ia, and Examples 38 through 43 in Table Ib, whichlist their embodiments, elemental analyses and melting points. Specificpreparations of Examples 1, 3, 4, 8, 9, 10, 11, 12, 17, 20, 37, and 41are set out below to illustrate the various methods of preparing the3-hydroxyisothiazoles of the invention.

EXAMPLE 1 Preparation of 4-bromo-3-hydroxyisothiazole To a solution of5.1 parts (0.05 mole) of 3-hydroxyisothiazole in 90 parts of ethylacetate, there was added dropwise 8.0 parts (0.05 mole) of bromine.After stirring for 12 hours, the resulting slurry was filtered to yield3.0 parts of 4-brom0-S-hydroxyisothiazole hydrobromide, M.P. 188 C.(dec.). Evaporation of the ethyl acetate filtrate left 3.7 parts ofwhite solid 4-bromo-3-hydroxyisothiazole having a melting point of 193-195 C.

EXAMPLE 3 Preparation of 5-chloro-3-hydroxyisothiazole In a one-liter,3-necked flash equipped with a mechanical stirrer, thermometer, anddropping funnel there were mixed 500 ml. of ethylene dichloride and 20.8g. (0.1 mole) of dithiodipropionamide. This mixture was stirred at -15C. and 42.5 g. (0.306 mole) of sulfuryl chloride was added dropwise over2 hours. On completion of the addition, the reaction slurry was allowedto warm to 25-30 C. and stirred overnight to assure complete reaction.The reaction slurry. was then filtered, and the precipitate was digestedin 150 ml. of hot water. The aqueous solution was filtered to removesome insoluble material and then cooled in ice to yield after filtrationand drying 4.0 g. of 5-chloro-3-hydroxyisothiazole as a tan crystallinesolid, M.P. 95-96 C.

EXAMPLE 4 Preparation of 4-bromo-5-chloro-3hydroxyisothiazole To asolution of 100 ml. of ethyl acetate and 6.8 g. (0.05 mole) of5-chloro-3-hydroxyisothiazole prepared in accordance with Example 3,there was added at 0 C. a solution of 8 g. (0.05 mole) of bromine in 25ml. of ethyl acetate. After addition the red reaction solution wasallowed to warm to room temperature, and after 1 hour, the solvent wasremoved under reduced pressure to leave 13.7 g. of dark orange solid.Treatment of this solid with water left, after drying, 8.7 g. of4-bromo-5-chloro-3-hydroxy isothiazole, M.P. 145147 C. from ethylacetate.

8 EXAMPLE 8 Halogenation of Z-betathioketoamide Thioacetoacetamidehydrochloride (126.7 parts, 0.826 mole) was slurried in 2250 parts ofethyl acetate and treated dropwise at 0 C. with 264 parts (1.652 moles)of bromine in an equal volume of ethyl acetate. After stirring for 12hours at 25 C., the slurry was filtered to yield 60.2 parts of a productwhich was primarily a mixture of 4 bromo-5-methyl-3-hydroxyisothiazoleand 5-methyl-3- hydroxyisothiazole hydrobromide having a melting pointof 177-180 C.

EXAMPLE 9 Preparation of 5-methylsulfinyl-4-cyano-3- hydroxyisothiazoleEXAMPLE 10 Preparation of 5-methylsulfonyl-4-cyano-3- hydroxyisothiazoleA solution of 4.1 parts (0.024 mole) of 5-methylsul=finyl-4-cyano-3-hydroxyisothiazole in 400 parts of acetone was treatedat 25 C. with 40 parts of an acetone solution containing 16.4 parts(0.05 mole) of m-chloroperbenzoic acid. After stirring for 2 days, theacetone was evaporated to leave a yellow solid residue, which upontreatment with diethyl ether gave 2.0 parts of solid 5-methylsu1fonyl-4-cyano 3-hydroxyisothiazole having a melting point of 231-233 C. (dec.).

EXAMPLE 11 Preparation of 4-carboxy-3hydroxyisothiazole To a solution of9.2 g. (0.08 mole) of 3-methoxyisothiazole in 20 ml. of glacial aceticacid was added drop wise at 25 C. a solution of 12.8 g. (0.08 mole) ofbromine in 20 ml. of glacial acetic acid. After stirring overnight theslurry which had formed was poured into 400 g. of ice-water and allowedto stand. The precipitated solid was extracted into ether, and theaqueous phase was neutralized with solid sodium bicarbonate andextracted with ether again. The combined ether extract was dried overanhydrous magnesium sulfate and evaporated to leave an oil residue. Thismaterial was distilled to give 11.1 g. (721%) of4-bromo-3-methoxyisothiazole, B.P. 70 C. (5 mm.). which solidified oncooling in ice.

To a solution of 38.8 g. (0.2 mole) of 4-bromo-3-methoxyisothiazole inml. of dimethylformamide was added 54 g. (0.6 mole) of cuprous cyanide.The mixture was stirred and heated at reflux for 1 hour. Then the reaction mixture was cooled to 25 C., and 40 g. 0.81 mole) of sodium cyanidein 120 ml. of water was added in portions. The mixture exotherrned to60-70 C. and was allowed again to cool to 25 C. The reaction solutionwas then extracted thoroughly with ether. The ether extracts were washedwith 10% sodium cyanide solution and then water. After drying overanhydrous magnesium sulfate and evaporation 23.4 g. (83%) of4-cyano3-methoxyiso-= thiazole was obtained as a white solid, M.P. 60-62C. after crystallization from ligroin (120).

To 195 m1. of 80% sulfuric acid at C. was added 12.5 g. (0.089 mole) of4-cyano3-methoxyisothiazole. The mixture was allowed to cool to roomtemperature over /2 hour. The temperature was then lowered to 10 15 C.and a solution of 17.9 g. (0.26 mole) of sodium nitrite in 35 ml. ofwater was added slowly beneath the surface of the liquid. After additionthe reaction was allowed to come to room temperature, then was heated to60 C. for several minutes and allowed to cool. The solution was thenpoured into 450 ml. of ice water to precipitate solid4-carboxy-3-methoxyisothiazole. After filtration, this latter crudeproduct was added to 200 ml. of 48% hydrobromic acid and heated at 80 C.for 2 hours to form a solution. The reaction solution was then cooled inDry-Ice to precipitate a solid product, which after filtration, washingwith water, and drying gave 8.50 g. (60%) of pure 4carboxy-3-hydroxyisothiazole, M.P.

202-4 (dec.). 1

EXAMPLE 12 Preparation of 4-carbamoyl-3-hydroxyisothiazole A solution of2.8 g. (0.02 mole) of 4-cyano-3-methoxyisothiazole prepared as inExample 11 in 30 ml. of 75% sulfuric acid was heated at 70 C. for 0.5hour. The solution was then cooled and poured onto ice to give afterfiltration and drying 0.95 g. of 4-carbamoyl-3- methoxyisothiazole, M.P.165-168 C. By continuous ether extraction of the aqueous filtrate anaddition 1.13 g. of 4-carbamoyl-3-methoxyisothiazole was obtained togive a total yield of 2.08 g. (66%). Following the procedure of Example11, the 4-carbamoyl-3-methoxyisothiazole was hydrolyzed with 48%hydrobromic acid to give 4-carbamoyl-3-hydroxyisothiazo1e, M.P. 222(dec.)-

EXAMPLE 17 Preparation of 4-cyano-5-butylamino-3-hydroxyisothiazolePotassium metal (3.90 g., 0.10 mole) was dissolved in 40 ml. oft-butanol and 20 ml. of tetrahydrofuran (THF). To this solution was thenadded 8.4 g. (0.10 mole) of cyanoacetamide in ml. of THF to form a thickyel1ow-slurry. After stirring for one hour, the mixture was cooled to 10C. and 11.5 g. (0.10 mole) of n-butylisothiocyanate in 20 ml. of THF wasadded slowly. After stirring at room temperature for three hours, asolution had formed. The solvent was then evaporated under vacuum, andthe residue was taken up in 400 ml. of water. The aqueous solution wasthen extracted with ether and acidified with 2 N hydrochloric acid. Thesolid which precipitated was collected and dried to give 8.4 g. (42%a-(N-n-butylthiocarbamoyl) cyanoacetamide.

The product from above (4.0 g., 0.02 mole) was dis solved in ml. ofethyl acetate and treated over 0.75 hour at 25 C. with 3.2 g. (0.02mole) of bromine in 30 ml. of ethyl acetate. The yellow precipitatewhich formed was filtered off, washed with water, and dried to give 2.25gm. (56%) of 4-cyano-5-butylamino-3-hy-= droxyisothiazole, M.P. 194-96C.

EXAMPLE 20 Preparation of B-hydroxyisothiazole zinc salt To a solutionof 20.2 g. (0.20 mole) of 3-hydroxyisothiazole in ml. of water was added8.14 g. (0.1 mole) of zinc oxide. The mixture was stirred at 50-60" C.for 1.5 hour, during which time the mixture turned to a. fairly thickwhite paste. The solid was removed by filtration and dried to give 23.75g. (90%) of 3-hydroxyisothiazole zinc salt, M.P. 300-305 C. (dec.).

EXAMPLE 37 Preparation of 3-hydroxyisothiazole morpholine salt To asolution of 5.0 g. (0.05 mole) of 3-hydroxyisothiazole in 10 ml. ofmethanol was added 4.3 g. (0.05 mole) of morpholine with an exotherm toabout 40 C. The solution was then cooled to 5 C. to precipitate a solid,which upon filtration and drying gave 6.5 g. (70%) of3-hydroxyisothiazole morpholine salt, M.P. 79-82 C.

EXAMPLE 41 Preparation of 3-hydroxyisothiazole maleic acid salt In 50ml. of ethyl acetate was dissolved 10.1 g. (0.10 mole) of3-hydroxyisothiazole and 5.8 g. (0.050 mole) of maleic acid by gentlywarming. Upon cooling the solid salt precipitated and was collected byfiltration to give 7.6 g. (48%) of 3-hydroxyisothiazole maleic acidsalt, M.P. -17 C.

TABLE I.-3-HYDROXYISOTHIAZOLE EXAMPLES z- --I 4 3 OH I 5 2N z k/Analysis Z Z M.P O H N S Halogen Example number:

1. Br H 193 195 20.20 (20.0) 1.17 (1.1) 7.73 (7.8) 17.31 (17.7) Br,45.09 (44.4) C H -170 27.61 (26.6) 1.95 (1.5) 9.73 (10.3) 21.78 (23.6)01, 26.15 (26.2)

01 05-00 20.20 (20.5 1.22 1.4 10.11 10.3) 23.20 23. e) 01, 23.23 (20.2001 145-147 17.43 10.3) 0. 01 (0.5) 0. 05 (0. 0) 15.17 (15.0 01 15145421.01 (21.1) 0. 01 (0.3) 7. so (3. 2) 18.58 (13.3) 01, 40.35 (41.7) H81-105 40.60 (41.7) 4.39 (4. 4) 11.60 (12. 2 25.6 (27.8) 01 122 32. 43(32.2 3.45 2.7 0.311 04 10.20 (21.5; 01, 22.53 23.3) 7-180 24.57 (24.72.76 (2. 1 7.21 7. 2 16.21 (16.5 Br, 41.12 41.2)

00011. 130100 31.77 (31.0 2.33 (2.1 14. as (14.3 301011. 231-233 20.70(20.4 1. s0 (1. 0) 13.22 13.7 30.11 (31.3; H 3 202-4 32.37 (33.1 2.29(2.07; 9.00 9.66 20. 63 (22.1 H 3 222 34.01 (33.3 2.63 (2.78 19.20 (19.422.30 (22.2 H 25.32 (24.7) 1.52 (1.37 10.31 (10. 2 21. 07 (21.0 SCH;240-41 31. 56 (31. 4) 2. 91 (2. 63; 7. 43 (7. 38 32. 12 (33. 7 son. 1200.31 31.88 (31. 0) 3.72 (3.20 14.22 (14.7) 33.13 (33.7) CQHlz-D Oil54.41 (58.4) 7.97 (8. 11) 7. 82 (7.57) 19. 10 (17.3) NHC4H0-n 194-6 48.70 (48. 8; 5.86 (5. 86; 21.04 (21.3) 16. 16 (16.3) NHCnHs 212-14 42. 95(42. 6 4. 26 (4. 17 24. 54 (24.8) 18. 68 (18. 9)

1 The number parenthesized represents the theoretical value. ascalculated, using the empirical formula of each compound. 1 A mixturecomprising 4-bromo-5-methyl-3-hydroxylsothlazo1e and5-methyl-3-hydroxylsothiazole hydrobtomtde.

a Decomposed.

TABLE Jim-SALTS F B-HYDROXYIBOTHIAZOLES Analysis Z Z 0 H N 8 MetalMiscellaneous H H 22.29 224. 9) 2.56 (3.05) 9.79 (9.69) 21.84 (22.1)15.24 (15.9) H2O, 15.0 H H 27. 27 27.1) 1.90 1.50) 9.32 (10.6) 21.20(24.1) 21.2 (24.6) H H 15.14 (14.5) 1.51 (0.81) 5.46 (5.65) 13.22 (12.9)42.45 (45.4) C1, 13.78 (14.3) H H 28.50 228. 2) 2.03 (1.6) 10.81 (11.0)24.00 (25.0) 9. 48 (21.8; H H 28.89 27.4) 1.88 (1.52) 10.87 (10.8) 24.20(24.3) 16.03 24.1 H H 29.10 (27.8) 2.29 (1.50) 11.10 (10. 7) 21.56(24.8) 13.50 (22.7) H H 28.60 (27. 8; 2.33 (1.50) 10.83 (10.7) 24.4024.8) 12.16 222. 7) H H 25.92 230.4 2.06 (1.69) 9.41 (11. 8; 19.00(27.0) 14.55 15.7) H H 15.43 18.0) 1.48 (1.10) 5.69 (7.0 12.85 (16.0)33.7 (50.0) H H 16.66 16.7) 1.51 (1.39) 3.92 (3.88) 9.95 (8. 91) 56.03(55.8) H Cl 20.63 21.6) 0.85 (0.60) 7.78 8.40) 18.02 19.2) 20.32 (19.6)01, 20.93 (21.2) C1 C1 17.60 17.9) 6.50 (69) 15.17 (15.9) 01, 32.08(35.2) H H 10.85 (10. 7) 0.84 (0. 6) 3.95 (4.16) 9.39 (9.53) 57.19(59.7) H H 11.16 (11.3) 0.79 (0.95) 4.07 (4.43) 10.40 (10.1) 65.94(63.1)

H H 0H1N (CHl)IC1TlIHfl-fl t-CsH11+NH=CHNHCaH11-t H H 62.18 (64.9) 10.53(10.6) 11.13 (11.4) n-C1oHzr+NH=CHNHC10H21-n H H 63.25 (67.8) 10.46(11.1) 9.30 (9.9) CtH|CH1 NHs H H 56.43 (57.7) 5.95 (5.8) 12.78 (13.4)

1 See footnote 1, Table I.

TABLE Ib.-SALTS OF 3-HYDROXYISOTHIAZOLES B 1 OH z' 1 H Analysis Examplenumber A Z Z O H N S Halogen as 01- H H 25.30 6-2) 2.68 (2. 90) 9.85(10.2) 22. 59 (23.3) 01,2 1.15 25.3 39 Nor H H 21.92 (22.1) 2.03 (1.84)16.18 (17.1) 19.21 (19.6) 40 H301 H H 2-6 20.0) 2.45 (1.67) 8.49 (7.74)29.45 35.4

41 CH=CH H H 37.85 (37.7) 3.696.1 4) s.s5 =(s.so) 20.07 20.1

42 -01CC0r H H -8 (3 9) 2 87 (2.74) 9.59 (9.59) 22.03 (21. 92) 43 Br- BrH 3.67 .8) 2 08 (1. 2) 5.56 5.37) 12. 36 (12.3) Br, 61.11 (61.2)

1 See footnote 1, Table I.

The novel hydroxyisothiazoles of this invention are biocidally activecompounds, and as such, are suitable for the control of livingorganisms, and particularly microorganisms. For this reason, they areespecially effective bactericidal, algaecidal, fungicidal, slimicidal,and pesticidal agents. Furthermore, these novel compounds possess theunexpected property of being resistant to inhibition by common additivesor contaminants such as lecithin, normal hose serum, alkylbenzenesulfonates, water-soluble lanolin, sodium chromate, sodium nitrite,glycerol, propylene glycol and the like.

In addition to the novel substituted B-hydroxyisothiazoles disclosedherein, it was also determined that several known hydroxyisothiazoleslikewise exhibit biocidal activity. These compounds which were known inthe literature but did not have any biocidal activity attributed to themprior to present disclosure include the following:

3-hydroxyisothi'azole, S-methyl-3-hydroxyisothiaz7ole,4-bromo-5-methyl-3-hydroxyisothiazole,4-cyano-5-methylthi0-3-hydroxyisothiazole,S-phenyl-3-hydroxyisothiazole,4-carbamoyl-5-anilino-3-hydroxyisothiazole, and4-cyano-5-anilino-3-hydroxyisothiazole.

Antibacterial activity was evaluated by the Serial Dilu-= tion Test(Broth Titer Test) wherein a series of broths containing varyingdilutions of a test compound and an organism are halved starting with121,000. The values ob tained which are shown in Table II and Table IIarepresent the maximum dilution at which the compound under evaluationrenders complete control of the organism. Staphylococcus aureus (S.aureus) and Escherichia coli (E. coli) were the bacterial organismsemployed in this test.

Fungicidal evaluation of the isothiazoles was carried out by thestandard slide spore germination test (cf. Phytopathology, 33, 627(1943), utilizing spores of Alternaria solani (Alt.), Sclerotiniafructicola (ScL) and Stemphylium sarcinaeforme (Stem.) or Botrytiscinerea (Bot), or by the Serial Dilution Test, employing Aspergillusniger (A. niger) and Rhizopus stolonifer (Rhz'z.) as test organisms. Thevalues in Table II for the results of the slide spore germination testare given in parts per million which efiectively controlled 50% of thespores. The values in Table IIa represent the maximum dilution at whichthe compound under evaluation completely con= trols the organism.

The 3-hydroxyisothiazoles of the invention are also effective asalgaecides. The algaecidal activity of the 3-hydroxyisothiazoles wasdetermined by the Fitzgerald Test (Applied Microbiology, 7, 205-211, No.4, 1959). Table III shows the parts per million of the3-hydroxyisothiazole under evaluation necessary for complete control ofthe organism. Chlorella pyrenoidosa (Chlorella) and Black algae(Oscilatorirz .712.) were the algae employed in this test.

Bacterlostatic Fungicidal evaluation evaluation Stem. Alt. Sol. (Bot!)S. aureus E. coli TABLE II.-MICROBIOLO GICAL ACTIVITY Example number:

75 strate the effectiveness of these compounds for seed treat;

ment. This involved slurrying two lots of 100 corn seeds each with thehydroxyisothiazole under evaluation at a level of 1 to 2 ounces perbushel of seed. For purposes of comparison, an untreated control wasalso included. After drying, the seeds were planted in a muck soilinfested with Pythium and having a high moisture content. The corn seedswere maintained in this soil for a week at about C. so as to permitinfection. Upon completion of this period of time, the temperature waselevated and maintained at about 21 to 27 C. so as to permit germinationof the non-infected seed. The number of seeds germinating were countedafter emergence of the plant and such data is set forth in Table III.

Evaluation of the hydroxyisothiazoles with regard to pesticidal activitydemonstrated their exceptional control of numerous nematodes, mites,insects, such as beetles and aphids, and the like. Some typicalnematodes, insects and mites which were controlled when contacted withthe compounds of this invention included the following: Northern rootknot nematode (Meloidogyne hapla),

Mexican bean beetle (Epilachna varivesta), black carpet beetle (Attagenus piceus), confused flour beetle (Tribolium confusum), granaryweevil (Sitophilus granarius), two spotted mite (Tetranychus urticae),house 'fly (Musca domestica), Southern armyworm (Prodem'a oridania),German cockroach (Blattella germania), and green peach aphid (Myzuspersicae).

Generally, control of a living organism is achieved in accordance withthis invention by contacting the organism with a hydroxyisothiazole inan amount which is effective to control said organism. Any of thetechniques known in the art may be employed to disseminate thehydroxyisothiazoles in a manner so as to achieve the desired contactwith the organism to be controlled. Spraying and fumigating are typicalof such techniques.

The compounds of this invention can be readily utilized as slimicides,algaecides, bactericides, and fungicides in any locus and particularlyin aqueous media, such as, for example, water-cooling systems, swimmingpools, paper pulp processes, aqueous polymer dispersions, water-basedpaints, and the like. In addition, these compounds and compositionscontaining them can function as, for example, fabric and leatherpreservatives, cosmetic preservatives, soap additives, sanitizingagents, such as in laundry soaps and detergents, and preservatives formetal working compounds, such as emulsifiable cutting oils,preservatives for fuels, fiber spin finish biocides, and the like.

In general, a locus subject to contamination by microorganisms can beprotected in accordance with this in-' vention by incorporating into thelocus a hydroxyisothiazole or a salt of a hydroxyisothiazole in anamount which is effective to control the microorganisms. The termcontamination" is meant to include any attack by microorganisms whichleads to a chemical or physical breakdown or disintegration of the locusas well as the proliferation of the microorganisms within the locuswithout an accompanying deleterious effect. The exact amount ofhydroxyisothiazole required will, of course, vary with the medium beingprotected, the microorganisms being con trolled, the particularhydroxyisothiazoles or compositions containing the hydroxyisothiazolesbeing employed and 16 the like. Typically, in a liquid medium, excellentcontrol is obtained when the hydroxyisothiazoles are incorporated intherange of 0.1 to 10,000 parts per million (ppm) or 0.00001 to 1% based onthe weight of the media. A range of 1 to 2000 ppm. is preferred.

The term control," as employed in the specification and claims of thisapplication, is to be construed as the effect of any means whichadversely affects the existence or growth of any living organism ormicroorganism. This effect may comprise a complete killing action,eradication, arresting in growth, inhibition, reduction in number, orany combination thereof.

Outstanding fungistatic activity by the isothiazoles was exhibited whenthey were employed as paint preservatives and paint fungistats.Microbial activity in water-based and oil-based paint emulsions iseffectively inhibited when these compounds are incorporated into thepaint. The isothiazoles are also highly active mildewcides for paintfilms when incorporated in paint formulations.

The hydroxyisothiazoles of this invention are especially useful asagricultural fungicides. As such, they are particularly valuable whenformulated in a fungicidal composition. Such compositions normallycomprise an agronomically acceptable carrier and the compounds disclosedherein as the active agent or agents. Where necessary or desirable,surfactants or other additives may be incorporated to give uniformlyformulated mixtures. By agronomically acceptable carrier is meant anysubstance which can be utilized to dissolve, dispense or diffuse thechemical incorporated therein without impairing the effectiveness of thetoxic agent and which does no permanent damage to such environment assoil, equipment and agronomic crops.

For use as pesticides, the compounds of this invention are usually takenup in an agronomically acceptable carrier or formulated so as to renderthem suitable for subsequent dissemination. For example, thehydroxyisothiazoles may be formulated as wettable powders, emulsionconcentrates, dusts, granular formulations, aerosols or flowableemulsifiable concentrates. In such formulations, the hydroxyisothiazolesare extended with a liquid or solid carrier and, when desired, suitablesurfactants are likewise incorporated.

Com-pounds of this invention may be dissolved in a water-miscible liquidsuch as ethanol, isopropanol, acetone, and the like. Such solutions areeasily extended with water.

The isothiazoles may be taken up on or mixed with a finely-particledsolid carrier, for example, clays, inorganic silicates, carbonates, andsilicas. Organic carriers may also be employed. Dust concentrates arecommonly made wherein hydroxyisothiazoles are present in the range of 20to For ultimate applications these concentrates are normally extendedwith additional solid from about 1 to 20%.

Wettable powder formulations are made by incorporating the compounds ofthis invention in an inert, finely divided solid carrier along with asurfactant which may be one or more emulsifying, wetting, dispersing orspreading agents or blend of these. The hydroxyisothiazoles are usuallypresent in the range of 10 to 80% by weight and the surfactants in from0.5 to 10% by weight. Commonly used emulsifying and wetting agentsinclude polyoxyethylated derivatives of alkylphenols, fatty alcohols,fatty acids and alkylamines; alkylarene sulfonates and dialkysulfosuccinates. Spreading agents include such materials as glycerolmannitan laurate and a condensate of polyglycerol and oleic acidmodified with phthalic anhydride. Dispersing agents include suchmaterials as the sodium salt of the copolymer of maleic anhydride and anolefin such as diisobutylene, sodium lignin sulfonate and sodiumformaldehydenaphthalene sulfonates.

One convenient method for preparing a solid formulation is to impregnatethe isothiazole toxicant onto the solid carrier by means of a volatilesolvent, such as ace- 1 7 tone. In this manner, adiuvants, such asactivators, adhesives, plant nutrients, synergists and varioussurfactants, may also be incorporated.

Emulsifiable concentrate formulations may be prepared by dissolving theisothiazoles of this invention in an agronomically acceptable organicsolvent and adding a solvent-soluble emulsifying agent. Suitablesolvents are usually water-immiscible and may be found in thehydrocarbon, chlorinated hydrocarbon, ketone, ester, alcohol and amideclasses of organic solvents. Mixtures of solvents are commonly employed.The surfactants useful as emulsifying agents may constitute about 0.5 to10% by weight of the emulsifiable concentrate and may be anionic,cationic or nonionic in character. Anionic surfactants include fattyalcohol sulfates or sulfonates, alkylarene sulfonates andsulfosuccinates. Cationic surfactants include fatty acid alkyl aminesalts and fatty acid alkyl quaternaries. Non-ionic emulsifying agentsinclude alkylene oxide adducts of alkylphenols, fatty alcohols,mercaptans and fatty acids. The concentration of the active ingredientsmay vary from 10 to 80%, preferably in the range of 25 to 50% For use asphytopathogenic agents, these compounds should be applied in aneffective amount sufficient to exert the desired biocidal activity bytechniques well known in the art. Usually, this will involve theapplication of the hydroxyisothiazoles to the locus to be protected inan effective amount when incorporated in an agronomically acceptablecarrier. However, in certain situations it may be desirable andadvantageous to apply the compounds directly onto the locus to beprotected without the benefit of any substantial amount of carrier. Thisis a particularly effective method when the physical nature of the hydroxyisothiazoles is such as to permit what is known as low-volumeapplication, that is, when the compounds are in liquid form orsubstantially soluble in higher boiling solvents.

The application rate will, of course, vary depending upon the purposefor such application, the hydroxyisothiazoles being utilized, thefrequency of dissemination and the like.

For use as agricultural bactericides and fungicides, dilute sprays maybe applied at concentrations of 0.05 to 20 pounds of the activehydroxyisothiazole ingredient per 100 gallons of spray. They are usuallyapplied at 0.1 to 10 pounds per 100 gallons and preferably at 0.125 topounds per 100 gallons. In more concentrated sprays, the activeingredient is increased by a factor of 2 to 12. With dilute sprays,applications are usually made to the plants until run-off is achieved,whereas with more concentrated or low-volume sprays the materials areapplied as mists.

The compounds of this inventon may be utilized as the sole biocidalagents or they may be employed in conjunction with other fungicides,insecticides, miticides and comparable pesticides.

The following Examples A through D illustrate several specificembodiments of the many uses of the isothiazoles of the invention.

EXAMPLE A Preservatives for cutting oils Both natural and syntheticcutting oils, that is, oils which are mixed with water and used ascoolants and lubricants in, for example, lathe and other metal-workingoperations, are extremely susceptible to microbial attack whenformulated for use. This microbial attack leads to emulsion is about 20to about 2000 parts per million.

the formulation was examined to determine whether the isothiazole waseffective in controlling microbial attack, and, if so, the formulationwas recontaminated. This examination and recontamination procedure wasfollowed for a period of six months.

Two types of cutting oils were employed in testing the isothiazoles. Inthe first formulation, the isothiazole was added to a 1:60 oil-wateremulsion of an emulsifiable cutting oil containing petroleum oil andspecial emulsifiers (commercially available as Gulfs Gulfcut SolubleOil). The inoculum for the first formulation was a naturallycontaminated oil emulsion. It was found that a concen tration of aboutto 250 parts per million of 3-hydroxyisothiazole was effective incontrolling microbial attack in the cutting oil formulation for sixmonths. Furthermore, 5-chloro-3-hydroxyisothiazole was effective in comtrolling microbial attack for one month (no examinations were made afterone month) at a concentration of 50 ppm.

In the second formulation, the isothiazole was added to a 1:40 oil-waterdilution of a synthetic cutting oil made up of triethanolamine,sulfonated red oils, sodium nitrite, an anionic free acid of a complexorganic grsphat e stgg, and water (commerciallyavailable as H. MillersHami= kleer No. 1591 Soluble Oil). The inoculum for the secondformulation was a naturally contaminated soluble oil emulsion to whichwas added Pseudomonas oleoverans one of the most troublesomecontaminants of cutting fluid emulsions. It was found that aconcentration of 250 to 500 parts per million of S-hydroxyisothiazolewas effective in controlling microbial attack in the synthetic cuttingoil formulation. By way of comparison, it was determined that 500 ppm.of ethylhexyldimethylalkylammonium cyclohexylsulfamate, a commercialcutting oil preserva= tive, was ineffective in controlling bacterialattack in the Hamikleer cutting oil formulation.

The above tests indicate the usefulness of the isothiazoles of theinvention as preservatives for cutting oil formulations.

EXAMPLE B Control of algae, bacteria, fungi, and slime in cooling towersA constantly recurring problem in water-cooling systems is theout-of-control growth of algae, bacteria, and fungi, and the associatedformation of slime. The isothiazoles of the invention;: are quiteelfective in controlling algae, bacteria, and fungi, and slime formationin watercooling systems, and especially in water-cooling towers. Whenused as a cooling tower microbicide, the isothiazole will generally beaddedat a concentration of about V2 to 1000 parts per million. Thepreferred concentration range of the isothiazole is about 1 to 250 partsper million.

The following test was employed to evaluate the isothiazoles as coolingtower microbicides.

A series of laboratory cooling towers, operated concurrently, was usedfor the evaluation study. The cooling tower liquid was an inorganicsalts medium, designed to promote algal development. Approximately 8liters of this liquid were held in the reservoir, at 35 C., andcontinuously recirculated over pine wood slats at a rate of 2.3 litersper minute. A similar, but more dilute medium was pumped continuouslyinto each cooling tower reservoir at a rate of ml./hr. This wassufficient to replenish the volume lost in evaporation and to providethe system with a bleed-off of approximately 8 liters in 3 days. Aconstant volume was maintained in the res ervoir by use of an over-flowdrain.

The cooling towers were heavily inoculated at the beginning of the studyand twice per week thereafter with microorganisms (algae, bacteria, andfungi) obtained from a large commercial cooling tower. If necessary, thefirst two weeks of operation were used to establish an adequatepopulation of microorganisms on the surfaces and in the reservoir, and,in addition, to determine volume losses due to evaporation. Whenstarting with a fouled tower, treatment was initiated by the addition ofthe isothiazole at double the intended dose. When starting with a cleantower, treatment was initiated by the addition of the isothiazole at themaintenance dose. The isothiazole was then added periodically, usuallyonce a week, to the diluting systems to restore the concentration levelsto the intended maintenance dose. Four factors were considered inevaluating the effectiveness of the isothiazoles as cooling-towermicrobicides-control of algae and control of non-algal slime asreflected in the appearance of the tower, and general control ofbacteria and fungi in the water itself. Three isothiazoles were testedby the above procedure and found to be effective at the indicatedminimum concentration in parts per million. These isothiazoles were3-hydroxyisothiazole, at 15 p.p.m., -chloro-3-hydroxyisothiazole, at 15p.p.m., and the zinc salt of 3- hydroxyisothiazole, at 15 p.p.m.

The above tests demonstrate the usefulness of the isothiazoles of theinvention as water-cooling system microbicides.

EXAMPLE C Paint film mildewcides Paint films from water-based andoil-based paints are quite susceptible to mildewing, especially whenapplied on exterior surfaces. Presently, various mercury compounds aregenerally used as paint mildewcides. However, these mercury compoundshave several disadvantages, including their susceptibility to sulfidestaining and their toxicity. The isothiazoles of the invention are quiteeffective as paint mildewcides without the disadvantages of themercurial mildewcides, and often with better performance than themercury compounds. The concentration of isothiazole which is added tothe paint can vary over a wide range depending on such factors as thetype of paint involved, the locality of application, and the type ofsurface on which the paint is applied. Generally, about 95 lb. to 20 lb.of isothiazole per 100 gallons of paint will be effective. The preferredrange of incorporation is about 6 lb. to 12 lb. of isothiazole per 100gallons of paint.

In order to evaluate isothiazoles as paint mildewcides, wood sticks werepainted with water-based paint formulations to which the isothiazolebeing tested had been added. The paint films were allowed to dry for twodays, were treated with a test fungus (Aspergillus niger or Aspergillusoryzae) and after 7 to days were examined for evidence of mildewformation. The following isothiazoles were tested as paint filmmildewcides by the above procedure and found to be effective ininhibiting the growth of fungus at the concentrations indicated (inpounds of isothiazole per 100 gallons of paint): 3-hydroxyisothiazole,at 4 lb./ 100 gal., S-chloro-3-hydroxyisothiazole, at less than 2 lb./100 gaL, and the zinc salt of 3-hydroxyisothiazole, at 4 lb./100 gal.

The above tests and data demonstrate the useful qualities of theisothiazoles when used as paint film mildewcides.

EXAMPLE D Preservatives for vinyl or acrylic emulsion polymerdispersions On storage, aqueous dispersions of vinyl or acrylic emulsionpolymers, such as those used in making water-based paints, may besubject to a buildup of microorganisms which may lead to the productioof odor or discoloration in the dispersion or to actual physical orchemical break down of the polymer. 9

Examples of such polymer dispersions include polyvinyl acetate;polyisobutylene; polystyrene; polymers of dienes, such as of isoprene,chloroprene, butadiene, including copolymers of butadiene with styrene,acrylonitrile or mixtures thereof; copolymers of (a) a soft acrylate,such as a (C -C alkyl acrylate (especially methyl acrylate, ethylacrylate, butyl acrylate, 2-ethylhexyl acrylate or Il'llX- turesthereof), with (b) at least one hard comonomer, such as methylmethacrylate, acrylonitrile, styrene, vinyltoluene, vinyl acetate, andvinyl chloride, and (c) about 0.5 to 8% by weight of ana,fi-monoethylenically unsaturated acid, such as acrylic, methacrylic,crotonic, or itaconic acid such as those described in Conn et al. US.Pat. 2,795,564, June 11, 1957; and blends of any of these polymerdispersions with each other or with similar polymers containing a polargroup, such as any of the blends mentioned in Scott U.S. Pat. 3,356,627,Dec. 5, 1967.

The isothiazoles of the invention are effective in controlling build-upof microorganisms in such aqueous polymer dispersions and in water-basepaints made from them, thus, preventing deleterious contamination of thedisper sion or paint. An advantage of using the isothiazoles aspreservatives is that in proper concentration they will also function asmildewcides after the polymer dispersion or paint has been used to makea coating or film. When employed as preservatives, the isothiazoles areusually incorporated in the polymer dispersion in a concentration rangeof about /2 to 10,000 parts per million. The preferred concentrationrange is about 1 to 2000 parts per million.

In order to evaluate the isothiazoles as preservatives for polymerdispersions, various samples of different types of emulsion polymerdispersions, to which an isothiazole had been added, were contaminatedwith an inoculum consisting of naturally contaminated dispersion of thesame type or with a culture of organisms isolated from naturallycontaminated dispersions of the same type. For a period of six months,the samples were examined monthly for microbial contamination and thenreinoculated with fresh inoculum.

The isothiazoles were evaluated as preservatives in several differenttypesof commercially available acrylic polymer dispersions, of the typedescribed in the Conn et al. and Scott U.S. patents mentioned above.Among the isothiazoles which were tested in one or more of such acrylicpolymer dispersions and found to give control of microbial activity at aconcentration of less than 1000 p.p.m. in the dispersion are3-hydroxyisothiazole, 5-chloro-3-hydro-xyisothiazole, and the zinc saltof 3-hydroxyisothiazole.

In addition to the above examples, the isothiazoles were found to beuseful as laundry sanitizing agents. A wide concentration range can beemployed in formulating detergents or soaps with the isothiazoles of theinvention as sanitizing agents. Generally, about 0.01 to 10% of theisothiazole will be added to the soap or detergent, and the preferredrange is about 0.05 to 5%. The isothiazole can also be added directly tothe wash water, generally at a concentration of about /2 to 1000 partsper million.

Several isothiazoles were tested by the AATCC Methods -1965 T and -1965T, referred to above, and found to give a bacteriostatic or aself-sanitizing residual on fabric aganist S. aureus and/or E. coli 100p.p.m. or less. Among these isothiazoles are 3-hydroxyisothiazole,5-chloro-B-hydroxyisothiazole, and the zinc salt of3-hydroxyisothiazole.

The isothiazoles were also found to be quite useful as microbicides infiber spin finish formulation, such as nylon spin finish formulations.In evaluating the isothiazoles in this application, samples of naturallycontaminated spin finish formulations were obtained and used toinoculate uncontaminated formulations to which an isothiazole had beenadded. After a one month incubation, the test formulations were examinedfor contamination, and then re contaminated. In one such test,3-hydroxyisothiazole was found to be very eifective in controllingmicrobial contamination in fiber spin finish formulations at aconcentration of 250 parts per million or less.

It is to be understood that changes and variations may be made withoutdeparting from the spirit and scope of the invention as defined by theappended claims.

We claim:

1. A compound of the formula Z TLOH Z 1 wherein Z is hydrogen, (C -Calkyl, carhoxy, (C -CQ-carbaI- koxy, carbamoyl, nitro, halogen, orcyano;

Z, when Z is cyano, carboxy, (C -C )carbalkoxy, or carbamoyl, ishydrogen, (C -C )allcyl, aralkyl of up to 8 carbon atoms, halogen, (C -C)alkylsulfinyl, aralkylsulfinyl of up to 8 carbon atoms, (C-cgalkylsulfonyl, aralkylsulfonyl of up to 8 carbon atoms, alkylamino ofup to 8 carbon atoms, or aralkylamino of up to 8 carbon atoms;

Z, when Z is nitro, is hydrogen, (C -Cgalkyl, aralkyl of up to 8 carbonatoms, or halogen;

Z, when Z is (C -C )alkyl, is hydrogen, (C C )alkyl,

aralkyl of up to 8 carbon atoms, or halogen;

Z, when Z is halogen, is hydrogen, aralkyl of up to 8 carbon atoms, orhalogen; and

Z, when Z is hydrogen, is aralkyl of up to 8 carbon atoms, or halogen,or a salt of a compound of the above for= mula and a strong acid, analkali metal cation, an allra= line earth metal cation, a transitionmetal cation, a quaternary ammonium cation, a quaternary phosphoniumcation, or a primary, secondary, or tertiary organic base cation. 2. Acompound according to claim 1 wherein Z is hy drogen.

3, A compound according to claim 2 wherein Z is halogen.

4. A compound according to claim It wherein Z is (C -C )alkyl.

5. A compound according to claim 1 wherein Z is halo gen.

6. A compound according to claim 5 wherein Z halogen.

7. A compound according to claim 5 wherein Z hydrogen.

8. A compound according to claim 1 wherein Z cyano, carboxy, (C -Ccarbalkoxy, or carbamoyl.

h. A compound according to claim 8 wherein Z (C -C alkylsulfinyl.

10. A compound according to claim 8 wherein Z (C -C )alkylsulfonyl.

11. A compound according to claim 1 wherein Z halogen.

12. A compound according to claim 1 wherein Z (C1-C4 alkyl.

13. A salt of a compound according to claim 1 and a strong acid.

as. A salt of a compound according to claim 1 and an alkali metalcation, an alkaline earth metal cation, a transition metal cation, aquaternary ammonium cation, a quaternary phosphoniurn cation, or aprimary, secondary, or tertiary organic base cation.

15. A compound according to claim 43 wherein Z' is halogen.

OTHER REFERENCES Crow et al., J. Org, Chem, 30, 2660-5 (1965).,

RICHARD J. GALLAGHER, Primary Examiner US. Cl. X,R,

